1. Field of the Invention
The present invention relates to a laser irradiation device and a method of manufacturing an organic light-emitting display (OLED) device via the laser irradiation device. The laser irradiation device and the method of manufacturing prevents portions of a donor substrate that correspond to a non-transmissive portion of a mask pattern from exposure to laser radiation that otherwise would occur due to scattering of a laser beam.
2. Description of the Related Art
Due to lightweight and thin characteristics, flat panel display devices have been used in place of cathode-ray tube display devices. Representative examples of flat panel display devices include a liquid crystal display (LCD) device and an OLED display device. The OLED display device can have superior luminance and superior viewing-angle characteristics as compared to the LCD device. The OLED display device can be implemented in an ultra-thin type design with no backlight. As described above, the OLED display device produces excitons by re-combining electrons and holes injected through a cathode and an anode in an organic thin layer and produces a specific wavelength of light based on the energy of the produced excitons.
OLED display devices are classified into either a passive matrix type or an active matrix type. The active matrix type includes a thin film transistor (TFT) circuit in its design. The passive matrix type is advantageous in that its display region is configured with a device having a simple matrix based on an anode and a cathode and therefore fabrication is simple. However, the passive matrix type is limited to small-sized display applications due to its low resolution, high operating voltage, short lifetime of materials, etc. In the active matrix type, a display region can exhibit stable luminance by including a TFT in each pixel and supplying a regular current to each pixel. In the active matrix type, high-resolution and large-sized displays can be produced due to low power consumption.
One method of forming red, green and blue (RGB) light emitting layers that implement full color in the OLED display device is by using a laser induced thermal imaging (LITI) method. The LITI method patterns a laser beam generated from a laser source using a mask pattern, forms patterned organic layer that includes a light emitting layer, irradiates, using the patterned laser beam, a donor substrate that includes a base substrate, a light to heat conversion layer, and a transfer layer that is an organic layer that includes the light emitting layer, and transfers a part of the transfer layer onto a device substrate. The LITI method is a dry process in which each light emitting layer can be precisely patterned.
The mask pattern of the laser irradiation device includes a transmissive region and a non-transmissive region, the non-transmissive region being produced by forming a scattering layer on a given region of a transparent substrate using an etching process. However, in the laser irradiation device using the mask pattern in which the scattering layer is formed in the non-transmissive region, laser radiation scatters into portions of the donor substrate that correspond to the non-transmissive region of the mask pattern, causing noise and interference. As a result, there is a problem in that an undesired region of the donor substrate is exposed to the laser beam due to this interference and noise.